Fractures of the thoracic and lumbar spine and thoracolumbar transition

Most spinal column injuries occur in the thoracolumbar transition, the area between the lower thoracic spine and the upper lumbar spine; over half of all vertebral fractures involve the 12th thoracic and 1st lumbar vertebrae. The high incidence of vertebral fractures in this region is due to special biomechanical factors that apply in the transitional sections of the physiological curvatures of the spinal column (lumbar lordosis, thoracic kyphosis) in this area.

Spinal column, from side and rear

Thoracic spine, side view

Lumbar spine, side view

How are injuries of the thoracic and lumbar spine classified?

Böhler was the first to publish a classification system for vertebral fractures in 1929. His system differentiated 5 subtypes. In subsequent years, various classification systems for vertebral fractures were introduced with respect either to the fracture type or fracture mechanism (such as those developed by Denis or Ferguson and Allen). The bony and ligamentous structures of the anterior and posterior column area of the vertebral segment and the intervertebral disc can be involved in all spinal column injuries.

Mobile segment, side view, ligamentous apparatus

Ligamentous apparatus, thoracic spine

In 1994, F. P. Magerl introduced a classification system for the assessment of injuries to the thoracic and lumbar spine that is still used as the standard assessment system today.

This classification system takes into account the forces acting upon the spinal column to cause the injury (compression, distractions, and translation/rotation forces) as well as the typical injury patterns observed in the vertebrae, intervertebral discs, and ligamentous apparatus as a result of the mechanics of an injury.

There are three distinct types:

Type A injuries are caused by compression forces

Type B injuries by distraction forces

Type C injuries by rotation forces

The three injury types A, B and C are each subdivided into three subtypes with three subgroups each.

Type A injuries: Vertebral body compression (compression injury)

Type A injuries are caused by axial forces. They affect the vertebral body with intact dorsal ligamentous structures:

Type A injury

A1: Depressed fractures (impaction fractures), with upper plate collapse and no involvement of the posterior vertebral margin. This is subdivided into the following:

A1.1: Upper plate depression

Upper plate depression

A1.2: Wedge fracture

A1.2.1: Cranial wedge fracture

Cranial wedge fracture

A1.2.2: Lateral wedge fracture

A1.3: Vertebral body impaction

Vertebral body impaction

A2: Fissure fractures, characterized by fissure formation in the sagittal or frontal plane, where the degree of dislocation of the individual fragments differs.

A2.1: Sagittal fissure fracture

A2.2: Frontal fissure fracture

Frontal fissure fracture

A2.3: Pincer fracture

Pincer fracture

A3: Burst fractures are frequently characterized by the shattering of the vertebral body with involvement of the posterior edge of the vertebra with the dorsal ligamentous apparatus intact. A3 fractures are frequently unstable and cause neurological symptoms due to the compression of the spinal cord resulting from the dislocation of the posterior fracture fragments with parts of the intervertebral disc into the spinal canal.

Type C injuries are either type A injuries in combination with additional rotation, or type B injuries in combination with rotation and shearing fractures. These fractures are in most cases unstable, with high rates of neurological complications.

What are the possible symptoms of thoracic and lumbar spine fractures?

The instability of spinal column injuries, and therefore the risk of neurological complications, increases over the progression from type A to type C. The following symptoms may be present, depending on the fracture type:

Pain (local, movement-induced, radiating)

Medullary symptoms with incomplete or complete paraplegia

Radicular symptoms

Spinal shock

Specific symptoms of additional secondary injuries

How is the injury diagnosed?

If a vertebral fracture is suspected, an accident victim must be treated with utmost caution. Examination, positioning, and transport must be carried out safety and gently so as not to provoke any worsening of the initial status.

Radiological diagnostics are based on conventional x-ray images of the thoracic or lumbar spine in 2 planes, though the pain experienced by the accident victim often makes it difficult to adjust the image planes with a high level of accuracy, compromising the value of the information obtained in the x-rays to a considerable degree.
Computer tomography with reconstruction images allows for exact imaging of the destroyed vertebral elements. Nuclear magnetic resonance tomography allows for the clear imaging of injuries of the spinal cord, spinal nerves, and ligamentous apparatus.

How are thoracic and lumbar spine fractures treated?

Objectives of surgical treatment of spinal column injuries:

In a complete or incomplete paraplegic syndrome, rapid decompression of the pinched spinal cord and spinal nerves must be achieved to improve the neurological symptoms or prevent further worsening.

The stability of the spinal column must be restored.

The correct axial position of the spinal column, in particular the sagittal profile with physiological spinal column curvatures (lordosis/kyphosis), must be reconstructed.

The fusion length (spondylodesis segments) must be selected so as to ensure the stability of the whole while fusing as few mobile segments as possible.

Early mobilization and rehabilitation to expedite the reintegration of the injured person into his or her private and professional environment.

Stable fractures of the thoracic or lumbar spinal column without neurological complications, such as impaction fractures of type A1, are treated conservatively. Unstable fractures, such as burst fractures of type A 3, flexion distraction injuries of type B, or rotation injuries of type C, undergo surgical treatment. Depending on the level of the injury along the spine and the extent of spinal cord and spinal nerve damage, a number of surgical options are available for the stabilization of thoracic and lumbar spine fractures with dorsal (from the back), ventral (from the front) or combined dorsoventral access.
The following surgical methods are frequently used in the surgical treatment of thoracic and lumbar vertebra fractures: